Test `[%mel.node ... ]`

  $ . ./setup.sh
  $ cat > dune-project <<EOF
  > (lang dune 3.8)
  > (using melange 0.1)
  > EOF
  $ cat > dune <<EOF
  > (melange.emit
  >  (target out)
  >  (libraries melange.node)
  >  (preprocess (pps melange.ppx)))
  > EOF
  $ cat > x.ml <<EOF
  > let require : Node.node_require = [%mel.node require] |> Option.get
  > let main = require##main |> Js.Undefined.getExn
  > let () = Js.log main##exports
  > EOF
  $ dune build @melange

  $ cat _build/default/out/x.js
  // Generated by Melange
  'use strict';
  
  const Caml_option = require("melange.js/caml_option.js");
  const Js__Js_undefined = require("melange.js/js_undefined.js");
  const Stdlib__Option = require("melange/option.js");
  
  const $$require = Stdlib__Option.get(Caml_option.undefined_to_opt(typeof require === "undefined" ? undefined : require));
  
  const main = Js__Js_undefined.getExn($$require.main);
  
  console.log(main.exports);
  
  module.exports = {
    $$require,
    main,
  }
  /* require Not a pure module */

  $ node _build/default/out/x.js
  {}

